# Sum Of Multiples

Given a number, find the sum of all the unique multiples of particular numbers up to
but not including that number.

If we list all the natural numbers below 20 that are multiples of 3 or 5,
we get 3, 5, 6, 9, 10, 12, 15, and 18.

The sum of these multiples is 78.

## Exception messages

Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to
indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not
every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include
a message.

To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
`raise Exception`, you shold write:

```python
raise Exception("Meaningful message indicating the source of the error")
```


## Submitting Exercises

Note that, when trying to submit an exercise, make sure the solution is in the `exercism/python/<exerciseName>` directory.

For example, if you're submitting `bob.py` for the Bob exercise, the submit command would be something like `exercism submit <path_to_exercism_dir>/python/bob/bob.py`.

For more detailed information about running tests, code style and linting,
please see the [help page](http://exercism.io/languages/python).

## Source

A variation on Problem 1 at Project Euler [http://projecteuler.net/problem=1](http://projecteuler.net/problem=1)

## Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.